Microarray analysis comparing gene expression profiles generated from tumors and from in vitro cultured cells. (a) y axis, 135 probesets (106 genes) showing low expression in secreted Frizzled-related protein 1 (sFRP1)-positive tumors and moderate-high expression in control tumors, in in vitro cultured sFRP1-positive and in control cells. (b) y axis, 84 probesets (62 genes) showing high expression in sFRP1-positive tumors, and low expression in control tumors, in in vitro cultured sFRP1-positive and in control cells. (a), (b) Left to right, columns represent six sFRP1-positive tumors, five control tumors, three MDA-MB-231/sFRP1 clones and three MDA-MB-231/control clones (from Figure 1a). Genes with high, moderate and low expression are indicated in red, black and green, respectively. (c) Normalized gene expression of CCND1 and CDKN1A in MDA-MB-231/sFRP1-P1 and control-P1 tumors, and in MDA-MB-231/sFRP1-P1 and control P1 in vitro cultured cells.